584 SUPPLEMENT 
in the state of foetus, but it attains its growth successively. 
All the parts become developed, and it is then that the 
capsule opens, to permit it to put forth its tentacula, to seize 
its nutriment, and perhaps to respire. The growth of the 
central part then becomes more rapid. It deposits calcareous 
matter in the middle. It sprouts more and more, and is 
developed by means of new polypi in indeterminate points, 
so that one might say that the polyparium is almost totally 
independent of the polypus, and that its hard part, or axis, 
is always softer towards the extremities of the branches, than 
at any other place. 
Chemical analysis has proved that the coral, or at least its 
axis, is entirely composed of carbonate of lime, for it com- 
pletely dissolves in nitric acid. 
Imperato was the first writer who made use of the term 
MADREPORE (Madrepora) which, in its application by 
subsequent naturalists, has undergone several. modifications. 
Without troubling our readers with an account of these, it 
will be sufficient to say that the name is now reserved to 
certain lamelliferous tree-like polyparia, the surface of which 
is bristled with projecting cellules. Their classification is 
unfortunately based only on a knowledge of the polyparium, 
or cretaceous mass produced by the animals, for of the latter, 
very little that is satisfactory has been ascertained. Imperato 
was the first who suspected that the madrepores of Linnzus 
belonged to animals. Rumph, who had occasion to observe 
a great number in the Indian seas, confirmed this opinion, 
but he observed in them nothing but a sort of animal jelly 
covering the polyparium. Finally, Peyssonel removed all 
doubts upon this subject, and to Donati and Cavolini, we are 
most indebted for any details respecting the species. 
Of the madrepores thus defined, none are known in the 
seas of Europe, and hitherto they have been met with only in 
those of South America and India. Fixed by their base at 
